Amplifier



July 10, 1923.

R. P. SILVERTHORN AMPLIFIER Filed Nov. 10. 1921 2 Sheets-Sheet l lllllllllllllll INVENTOR A. A 5/7uerf/lorfl, Br

ATTORNEYS July 10, 1923 1,461,685

R. P. SILVERTHORN AMPLIFIER Filed Nov. 10. 1921 2 Sheets-Sheet 2 INVENTOR E PS/YUerf/YO/fl, BY

A TTORNE/S Patented July 10, 1923..

UNITED. STATES RUFUS PAUL SILVERTHORN, OF MARION, OHIO.-

AMPLIFIER.

To all whom it may concern:

Be it known that I, RUFUS P. SILVERTHORN, a citizen of the United States, and a resident of Marion, in the county of Marion and State of Ohio, have invented a new and Improved Amplifier, of which the following is a full, clear, and exact description.

This invention relates to improvements in sound amplifiers for phonographs, an object of the invention being to provide an amplifier which is so constructed that it will bring out tones otherwise lost in the playing of a record.

A further object is to provide a distinctly novel means for suspending the amplifier directly under the tone arm of a phonograph so that the amplifier does not contact with the cabinet of a phonograph and the nuisance of cabinet vibration is entirely done away with.

A still further object is to provide improved means for strengthening and bracing the mouth of the horn of the amplifier .so that it may be conveniently supported in the manner above described without affecting the character of the sounds transmitted therethrough.

Another object is to provide an amplifier which will be simple and practical in construction, strong, durable and efficient in use, and one which can be manufactured with comparative economy.

With these and other objects in view, the invention consists in certain novel features of construction and combinations and arrangements of parts as will be more fully hereinafter described and pointed out in the claims.

In the accompanying drawings:

Figure 1 is a front end view of my improved amplifier;

Figure 2 is a bottom plan view thereof;

Figure 3 is a view in longitudinal section on the line 33 oi Figure 1,-the dotted lines indicating a phonograph cabinet; and

Figure 4 is a view in longitudinal section 1 on the line 4-4 of Figure 3.

Referring in detail to the drawings, my improved amplifier includes a horn 1 cf substantially rectangular cross section. This horn is tapered increasing gradually in width from the throat to the mouth. Tt will be noted that the material forming the four walls of the horn is also of increased thickness adjacent the throat of the horn and is Application filed November 10, 1921. Serial No. 514,297.

relatively thin adjacent the mouth thereof.

The reference numeral 2 denotes the stem of the amplifier located at right angles to the plane of the horn. The stem is square in cross section, as seen most clearly in Fig ures l and 4 and is formed with a. centrally located tapered passageway 3 therein which communicates at its lower wider end with the throat of the horn. It will be noted that the stem 2 is reduced at its upper end, as indicated at 4 so that it may conveniently fit an opening in the top of a phonograph cabinet. I have indicated a cabinet in dotted lines at 5 and have also indicated in dotted lines at 6, the base of a tone arm which is in direct vertical alignment with the stem of the amplifier and communicates therewith.

A supporting bar 7 carried by the stem of the horn and projecting laterally on each side thereof is supported upon a pair of blocks 8 fixed to the rear wall of the cabinet, as seen most clearly in Figure 4. Bump er pads 9 secured lower down upon the rear wall of the cabinet cooperate with the blocks 8 and bar 7 to hold the amplifier against movement in the cabinet and at the same time support the same so that it does not contact at any point with the cabinet. This method of suspending the amplifier safeguards against the highly undesirable cabinet vibrations which sometimes ensue when the amplifier is directly connected to the cabinet.

Because of the fact that the amplifier as suspended in the manner above described, and also because of the fact that the mouth of the horn is of relatively thin material, it is necessary to provide a frame composed of a plurality of tonal strips 10, around the mouth of the horn to strengthen the same. Y

Such strips are called tonal strips for want of a better term, because when present and when constructed as shown in the drawings, they improve the tonal qualities of the sounds when the latter are thrown out by an amplifier which would otherwise blast. These strips may be attached to the horn in any approved manner, but it will be noted that the strips 10 on opposite sides oi each of the four corners of the horn are disconnected from the horn mouth by means of elongated cut-away portions, as shown clearly in Fig. l. The lower strip 10' may be connected to the rear end oi the bottom of the horn by a bridge 11, as such a relation of the parts-has been found in practice to add to the resonant qualitles.

It will be noted, with particular reference to Figures 1 and 4, that the interior of the horn adjacent the throat is gradually curved or tapered, as indicated at 12 so that it curves gradually into the circular tapered passage 3 of the stem. This feature, however, is conventional in difi'erent types of amplifiers and might be considerabl varied.

lthough I have illustrated one of the preferred embodiments of my invention, i-t will be evident that various slight changes self to the precise details of construction,

but shall consider myself at liberty to make such slight changes and alterations as fairly fall within the spirit and scope of the appended claims.

I claim:

1. A tone amplifier for phonographs, including a horn, and a frame around the mouth of the horn, said frame being disconnected from the horn mouth at intervals around the horn, the length of such disconnected parts of the frame being several times greater than the maximum lateral dimension of the frame.

2. A tone amplifier for phonographs, including a horn, said horn being rectangular in cross-section at its mouth, and strips on the exterior of the horn at each of its four sides and joined at the four corners of the horn and connected to the horn at said corners but disconnected from the horn along their lengths at points removed from the corners.

RUFUS PAUL SILVERTHORN. 

